Semiconductor Chip Mounting via Temperature-Controlled Adhesive Release
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Solution Overview
Problem
Existing methods for mounting miniaturized semiconductor chips, such as micro LEDs, face challenges in achieving stable and accurate attachment due to the potential for adhesive residue left behind, which affects the variance in adhesive layer thickness and mounting precision.
Innovation Solution
A method involving sequential steps: affixing a semiconductor chip's second face to an adhesive sheet, removing the carrier substrate, reducing adhesive strength, and mounting the chip on a circuit board while maintaining temperature control to prevent thermal contraction and ensure accurate placement without residual adhesive.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the adhesive layer is used to bond the semiconductor chip to the carrier substrate, then the mounting is achieved, but the adhesive layer may be left behind on the semiconductor chip causing variance in mounting precision
Solution Approach 1:
The adhesive function is segmented into two distinct stages: first, the adhesive sheet bonds the semiconductor chip to the carrier substrate for stable handling and transport; second, the adhesive strength is reduced to enable clean separation without residue. This segmentation allows each stage to optimize for its specific function without compromising the other.
Solution Approach 2:
The adhesive strength is made dynamic rather than static. The adhesive sheet's adhesive strength is changed over time through temperature control - maintained at a higher level during chip handling and transport, then reduced at the mounting stage to facilitate clean separation. This dynamic adjustment resolves the contradiction between needing strong bonding and clean release.
2Ease of operation
If the adhesive strength of the adhesive sheet is reduced by heating, then the semiconductor chip can be separated from the adhesive sheet, but thermal contraction may occur affecting mounting accuracy
Solution Approach 1:
The adhesive strength reduction is performed as a preliminary action before the actual mounting operation. By heating the adhesive sheet and semiconductor chip to reduce adhesive strength beforehand, the chip can be cleanly separated from the adhesive sheet before being mounted on the circuit board, preventing residue-related positioning errors.
Solution Approach 2:
The adhesive strength parameter is changed through temperature control. By heating the adhesive sheet and semiconductor chip to a specific temperature, the adhesive strength is reduced to a level that allows easy separation. The temperature parameters are carefully controlled to achieve the desired adhesive strength reduction while minimizing thermal contraction effects.
3Manufacturing precision
If temperature control is applied during mounting, then thermal contraction is prevented and mounting accuracy is improved, but process complexity increases
Solution Approach 1:
The temperature control system serves multiple functions simultaneously: it reduces adhesive strength of the adhesive sheet, prevents thermal contraction of the semiconductor chip and circuit board, and maintains overall process stability. By making the temperature control system multi-functional, the patent avoids adding separate systems for each function, thereby limiting the increase in overall complexity.
Solution Approach 2:
The temperature control functions are merged into a coordinated system that manages multiple aspects of the mounting process. The heating mechanisms for adhesive strength reduction and thermal contraction prevention are integrated and controlled together, reducing the need for separate independent control systems and simplifying the overall device architecture.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for stable and accurate mounting of semiconductor chips by eliminating residual adhesive and maintaining temperature consistency, enhancing the joint strength between the chip and circuit board while preventing misalignment or incorrect orientation.
Implementation Method 1
an adhesive sheet affixation step of affixing a second face, which is a face of the semiconductor chip on the opposite side from the first face held on the carrier substrate, to an adhesive sheet
Implementation Method 2
the adhesive strength reduction step involves heating the adhesive sheet and the semiconductor chip to a specific temperature to reduce the adhesive strength
Implementation Method 3
a mounting step of mounting the semiconductor chip on the circuit board by holding the first face side of the semiconductor chip with a head
Implementation Method 4
controlling the heating of the head and the mounting table such that the semiconductor chip can be mounted on the circuit board while maintaining the semiconductor chip at the specific temperature
Data Source
AI summary
A mounting method is a method for mounting a diced semiconductor chip having a first face that is held on a carrier substrate and a second face that is an opposite face of the first face on a circuit board placed on a mounting table. The mounting method includes affixing the second face of the semiconductor chip to an adhesive sheet, removing the carrier substrate from the semiconductor chip, reducing an adhesive strength of the adhesive sheet, and mounting the semiconductor chip on the circuit board by holding a first face side of the semiconductor chip with a head to separate the semiconductor chip from the adhesive sheet, and joining a second face side of the semiconductor chip to the circuit board.